JP2019212877A - Heat radiating part-equipped metal base printed circuit board and heat radiating fin forming method - Google Patents

Abstract

To provide a heat radiating part-equipped metal base printed circuit board that can be reduced in size while increasing the heat dissipation efficiency by forming a heat radiating fin of a radiator, which is formed upright using a raising tool, almost perpendicular to the plane of a metal plate, and a heat radiating fin forming method.SOLUTION: A metal base printed circuit board 1 includes a heat radiating part 5 in which a metal foil 3 is bonded to one surface 2b of a metal plate 2 having a predetermined thickness, and a plurality of plate-like heat radiating fins 5a formed upright at predetermined intervals are integrally formed on the other surface 2b of the metal plate 2. The plurality of plate-shaped heat radiating fins 5b are formed upright from the metal plate 2 so as to have substantially the same thickness from a base end integrally connected to the metal plate 2 to a tip thereof, and the plate thickness of a bottom surface 2e formed between the adjacent heat radiating fins 5b of the heat radiating part 5 is formed smaller than the plate thickness of the metal plate 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a metal base printed circuit board used in the field of electronic equipment, and more specifically, a metal base printed circuit board integrally formed with a heat radiating portion having heat radiating fins for radiating heat generated from electronic components and the like, and heat radiating fin formation Regarding the method.

  With the demand for higher performance and smaller size of electronic devices, circuit components have been miniaturized, densified, and highly functionalized, and are mounted on a circuit board at high density. For this reason, the temperature of circuit components is rising, and heat dissipation is very important. Conventionally, various methods have been proposed for heat dissipation, and some of them have been put to practical use.

As an example, Japanese Patent No. 5057221 (Patent Document 1) discloses a metal base printed board having a heat radiation portion including a plurality of plate-shaped heat radiation fins. The heat radiating fins of the heat radiating portion are formed by standing up a plurality of plate-shaped heat radiating fins at predetermined intervals by digging up the metal base printed board and digging it up with a tool.

JP-A-2005-93582

  As shown in Patent Document 1 described above, when a heat radiating fin is formed on a metal base printed board using a digging tool, the heat radiating fin 101 curls and rises from the metal plate 100 as shown in FIG. The thickness of the base end side of the radiating fin 101 is thicker and gradually thinner as it reaches the tip. For this reason, the space | interval G1 of the base end side of the adjacent radiation fin 101 is narrow, and the space | interval G2 of the front end side is formed wide. When the heat radiation fin 101 of this form is used as a heat radiator, for example, when the heat 103 generated from the heat source 102 such as an electronic component disposed on the metal base printed board is radiated, the heat 103 is converted into the metal plate 100 as indicated by a dotted line. The heat is dissipated between the heat radiation fins 101 and the heat radiation fins 101. Since heat has a property of rising in the vertical direction, when heat is dissipated from between the heat radiating fins 101, if the heat radiating fins 101 are curled, the heat 103 indicated by a dotted line meanders while hitting the side surfaces of the heat radiating fins 101. Rise. For this reason, the heat dissipating fins 101 may be reheated, which is a factor of reducing the heat dissipating efficiency.

  In order to quickly raise the heat 103 radiated through the metal plate 100, it is desirable that the radiating fins are vertically formed upright. A radiator having such a vertical radiating fin 101 is generally manufactured by extruding or casting a metal material, and this radiator is attached to an electronic component with heat generation disposed on a printed circuit board. Yes. However, the extrusion process or the casting process inevitably has a problem of increasing the size because the thickness and interval of the heat dissipating fins cannot be reduced. On the other hand, the method of forming the radiating fins using the digging tool can increase the radiating area and increase the radiating efficiency by reducing the thickness and spacing of the radiating fins. There was no means to form.

  Accordingly, an object of the present invention is to increase the heat dissipation efficiency and reduce the size of the heat dissipation part by forming the heat dissipation fins of the heatsink standing upright using a digging tool substantially perpendicular to the plane of the metal plate. An object of the present invention is to provide a metal base printed circuit board and a method for forming a radiation fin.

  In order to solve the above-described problems, a metal base printed board with a heat dissipation portion according to the present invention has a metal foil bonded to one surface of a metal plate having a predetermined thickness with thermal conductivity, and the other metal plate. A metal base printed board having a heat radiating portion integrally formed with a plurality of plate-like heat radiation fins standing upright at predetermined intervals on the surface, wherein the plurality of plate-like heat radiation fins are the metal A bottom plate formed between the radiating fins adjacent to the heat radiating portion, which is vertically formed from the plate and has a substantially equal thickness from the base end portion to the tip end integrally connected to the metal plate. The gist is that the thickness is smaller than the thickness of the metal plate.

  In addition, a method of forming a plurality of plate-like heat radiation fins that are vertically formed at predetermined intervals on the other surface of the metal base printed board is a digging tool in which a blade portion is formed on a tip side that is moved by a moving device. Digging up and forming the inclined plate-like fins by moving toward the one side of the metal plate in a state having a predetermined angle with respect to the other side of the metal plate, and digging up A straightening process in which the tool is lifted in the vertical direction and the blade portion is brought into contact with the inclined fin while standing uprightly with respect to the plane of the metal material, and the digging tool is separated from the next fin by a predetermined interval. The gist of the invention is to erectly form the plurality of plate-like heat dissipating fins by sequentially repeating the retreating step of retreating to the position where the digging occurs.

  According to the metal base printed board with a heat radiating portion according to the present invention, a plurality of plate-shaped heat radiating fins are vertically formed from the metal plate, and the thickness from the base end portion integrally connected to the metal plate to the tip is increased. Because it is formed almost equally, heat generated from heat sources such as electronic parts arranged on the metal base printed board rises smoothly from the heat radiating fin in the vertical direction, meandering while hitting the side surface of the other heat radiating fin Since the failure is prevented, the heat dissipation efficiency of the metal base printed board can be increased. In addition, since the thickness of the bottom surface formed between adjacent radiating fins is smaller than the thickness of the metal plate in the radiating portion, heat generated from a heat source such as an electronic component can be radiated in a short time. Therefore, it is possible to dissipate heat from the electronic components and the like more efficiently. Furthermore, since the heat radiating portion is formed integrally with the metal plate itself constituting the printed circuit board, the configuration is simplified, and the component cost and the manufacturing cost can be reduced.

  According to the method for forming a heat radiating fin of a metal base printed board according to the present invention, a tool for digging up on the other surface of a metal plate having a good thermal conductivity in which a metal foil is bonded to one surface via an insulating adhesive layer. After the digging process of standing and forming the inclined plate-like fin, the straightening process is performed easily by raising the digging tool in the vertical direction and bringing the blade part into contact with the inclined fin by the correction process. Vertical radiating fins can be formed. Also, since the heat sink is formed by digging up the metal plate to form the heat sink fin, the thickness of the bottom surface between adjacent heat sink fins can be made thinner than the plate thickness of the metal plate. Can be manufactured.

  It is a perspective view which shows the Example of the metal base printed circuit board with a thermal radiation part concerning this invention.   It is a sectional side view which shows the metal base printed circuit board with a thermal radiation part shown in FIG.   It is a side view which shows an example of the formation method of a radiation fin.   It is a perspective view which shows the metal base printed circuit board in which a radiation fin is formed.   It is explanatory drawing which shows the movement locus | trajectory of a digging tool.   (A) thru | or (H) is process explanatory drawing which shows the formation process of a radiation fin.   (A) thru | or (D) is process explanatory drawing which shows the other Example of a correction process.   It is explanatory drawing which shows the heat dissipation state of the radiation fin by this invention.   It is explanatory drawing which shows the heat dissipation state of the conventional curled radiation fin.

  The metal base printed circuit board with a heat radiation part according to the present invention has a metal foil bonded to one surface of a metal plate having a predetermined thickness with thermal conductivity, and the other surface of the metal plate is perpendicular to the other surface at a predetermined interval. A metal base printed board having a heat radiation part integrally formed with a plurality of plate-like heat radiation fins formed upright, wherein the plurality of plate-like heat radiation fins are vertically formed from the metal plate, and the metal The thickness from the base end portion integrally connected to the plate to the tip is formed to be substantially equal, and the thickness of the bottom surface formed between the heat dissipating fins adjacent to the heat dissipating portion is set to be greater than the plate thickness of the metal plate. It is formed small.

  Next, a metal base printed board with a heat radiating portion according to the present invention will be described in detail with reference to the drawings. A metal base printed board 1 shown in FIG. 1 and FIG. 2 uses a metal plate 2 such as copper, iron, iron-nickel alloy, aluminum, or aluminum whose surface is anodized as a base substrate, and this metal. A metal foil 3 such as a copper foil is bonded to one surface 2a of the plate 2 via an insulating adhesive layer (hereinafter referred to as an insulating adhesive layer 4). The insulating adhesive layer 4 uses, for example, a thermosetting resin such as a high heat-resistant epoxy resin as a base resin. Furthermore, in order to give high heat dissipation, it is desirable to blend a fine particle inorganic filler. As is well known, a predetermined wiring pattern is formed on the metal foil 3 by chemical etching. If necessary, a resist made of an electrically insulating film is coated except for the land of the wiring pattern.

  And the heat radiating part 5 is integrally formed in the predetermined position of the other surface 2b spaced apart from the one end side 2c of the metal plate 2. The heat dissipating part 5 is composed of a plurality of small small fins 5a, followed by a plurality of thin plate-shaped heat dissipating fins 5b formed at the same height. The small fins 5a are formed so as to increase sequentially from one end side 2c of the metal plate 2 to the heat radiating fins 5b side. The base end portions of the small fins 5a and the radiating fins 5b are integrally connected from the other surface 2b of the metal plate 2 as shown in FIG. Further, the heat radiating fins 5b are formed perpendicular to the plane of the metal plate 2 and are erected at the same interval.

  Since the plate | board thickness of the small fin 5a and the radiation fin 5b is formed by digging up from the one surface of the metal plate 2, it can be made thin. For example, as the heat radiating part 5 used in the small electronic component, the heat radiating fin 5b preferably has a thickness of about 0.03 mm to 1.0 mm. Moreover, the space | interval of each radiation fin 5b is arbitrarily set as 0.01 mm or more. And the plate | board thickness of the bottom face 2e formed between the adjacent radiation fins 5b is formed smaller than the plate | board thickness of the metal plate 2. As shown in FIG. In addition, you may form so that the plate | board thickness or space | interval of each radiation fin 5b may each differ.

  Next, a method of forming the small fins 5a and the heat radiating fins 5b of the heat radiating portion 5 of the metal base printed board 1 shown in FIGS. 1 and 2 will be described with reference to FIGS. The metal plate 2 is appropriately selected from copper and aluminum as a metal plate having good thermal conductivity and good machinability. The plate thickness of the metal plate 2 is 0.5 mm to several mm used in a normal electronic circuit. Then, a metal foil 3 such as a copper foil is bonded to one surface 2a of the metal plate 2 in advance via an insulating adhesive layer 4, and a predetermined wiring pattern is formed on the metal foil 3 by etching. And configured as a metal-based printed circuit board. In the state before the heat radiating portion 5 is formed, no electronic component is disposed. After the metal plate 2 is placed on a fin forming apparatus (not shown), the other side 2b small fins 5a and the heat radiating fins 5b of the metal plate 2 are formed upright by the digging tool 6.

  As shown in FIG. 3, the digging tool 6 has a blade portion 6 a perpendicular to the moving direction at the tip on the bottom surface side, and the width thereof is a width necessary for the heat radiating portion 5 as shown in FIG. 4. Is set. Incidentally, the width of the blade portion 6a of the digging tool 6 is set to be smaller than the width of the metal plate 2 configured as a metal base printed board. Further, as shown in FIG. 3, the digging tool 6 is attached to a driving device (not shown) so as to be inclined at a predetermined angle θ so that the rear end side becomes higher with respect to one surface of the metal plate 2. The inclination angle θ is appropriately set according to the height of the heat radiating fin 5b, the plate thickness, the material of the metal plate 2, or the like, but is set to approximately 5 degrees to 20 degrees. Although both sides in the width direction of the digging tool 6 are formed substantially at right angles, both sides on the bottom surface side where the blade portion 6a is formed may be formed in a tapered shape or an arc shape that becomes narrower as it reaches the bottom surface. .

  The digging tool 6 is controlled by the driving device so as to move as shown in FIG. a is a digging process, in which the digging tool 6 moves forward with the inclination angle θ maintained, and the metal plate 2 is formed to stand upright. Next, b is a correction process, in which the fin 6 is dug up from the position where the fin is erected and the tool 6 is raised vertically to bring the blade portion 6a into contact with the inclined fin and perpendicular to the plane of the metal plate 2. Orthorectify. c is a retreating process, in which the excavating tool 6 is retracted to a position where an excavation allowance D for excavating the next fin is obtained, and a series of circulation operations in which the blade 6a is brought into contact with the metal plate 2 by the descending process of d. Is repeated.

  First, as shown in FIG. 6A, after the blade portion 6a of the digging tool 6 is brought into contact with a predetermined position on one side farther from the one end side of the metal plate 2, the digging process of a shown in FIG. Thus, when the digging tool 6 is inserted into the metal plate 2 in the direction of the arrow having a predetermined angle θ by a driving device (not shown), the blade portion 6a of the digging tool 6 bites into the one surface 2b of the metal plate 2 As shown in FIG. 6A, the small fin 5a having a low height and a thin thickness is formed upright. At this time, it is desirable to set the pressure for inserting the digging tool 6 into the metal plate 2 so as not to deform or stress the metal plate 2. For this reason, since the depth at which the digging tool 6 is inserted is shallow, the small fins 5a are formed upright and low.

  After the blade portion 6a of the digging tool 6 stands and forms the small fin 5a, as shown in FIG. 6B, the blade portion 6a of the digging tool 6 is moved from that position as in the straightening step b shown in FIG. Ascend vertically. At this time, the blade portion 6a is raised uprightly perpendicularly to the plane of the metal plate 2 while being brought into contact with the inclined small fin 5a.

  Next, as shown in FIG. 6 (C), the digging tool 6 is moved as in the retreating step c shown in FIG. 5, and the blade 6a is moved to the position where the digging allowance D on the upstream side (the left side in the drawing) is obtained. 5 is brought into contact with the lowering step of d, and the next small fin 5a higher than the previous small fin 5a is erected by performing a digging process by digging deeper than when the previous small fin 5a is erected. Form. Also for the next small fin 5a formed upright in this manner, the blade portion 6a is raised in the vertical direction as in the straightening step b shown in FIG.

  Thereafter, the digging process shown in FIG. 6D, the correction process shown in FIG. 6E, the retraction process shown in FIG. 6F, and the lowering process are sequentially repeated, and the digging tool 6 is digging deeply in order. The small fins 5a are erected higher than the small fins 5a, and the small fin forming process is terminated when the blade 6a reaches a predetermined depth.

  Subsequent to the formation process of the small fins 5a, the process proceeds to the formation process of the radiation fins 5a, and a plurality of radiation fins 5a having the same height as shown in FIG. 2 are formed. That is, after the last formed small fin 5a is digged from the position where the upstream digging allowance is obtained, the blade 6a of the tool 6 is brought into contact with the metal plate 2 and then kept at a predetermined depth while maintaining the inclination angle. The digging process shown in FIG. 6 (G) is performed by moving until it reaches. Thereafter, the heat-radiating fin 5a is erected vertically with respect to the plane of the metal plate 2 by performing the correction process shown in FIG. Subsequently, similarly to the above-described forming process of the small fins 5a, the digging process, the correction process, the retraction process, and the lowering process are sequentially repeated by the blade portion 6a of the digging tool 6 so that the plurality of radiating fins 5a stand up. It is formed.

  As described above, the radiating fins 5a are vertically formed on the metal plate 2 by the digging tool 6 so that the bottom surface 2e is formed between the adjacent radiating fins 5a. It is formed smaller than the plate thickness of 2.

  As described above, when the correction process is performed by the blade part 6a of the digging tool 6, the radiation fin 5a is inclined at the blade part 6a side of the inclined sliding contact surface 6b because the radiation fin 5a is inclined at the start of the correction process. And the side surface of the radiation fin 5a abut. Thereafter, when the digging tool 6 is moved in the vertical direction, the radiating fin 5a is pressed in the vertical direction while the sliding contact surface 6b and the side surface of the radiating fin 5a are in sliding contact with each other. Make sliding contact. However, in the straightening process, the load is most applied to the blade part 6a of the digging tool 6 at the start of the straightening process, and thereafter the load on the blade part 6a decreases as the radiating fin 5a stands up. For this reason, in the straightening process, the sliding contact surface 6b is initially subjected to a load, and then the load becomes smaller as it stands up. Therefore, the load on the blade portion 6a is reduced, and thus the life of the digging tool 6 is adversely affected. The effect is reduced.

  As described above, by performing the process of forming the heat radiating fins 5, the heat radiating portion 5 in which a plurality of heat radiating fins 5b perpendicular to the metal plate 2 is formed as shown in FIGS. Thus, by forming the vertical radiating fins 5b, as shown in FIG. 8, for example, heat 8a generated from the heat source 8 such as an electronic component is radiated through the metal plate 2 as shown by the dotted line. However, since the heat 8a has a property of rising in the vertical direction, the heat 8a is smoothly raised from between the heat dissipation fins 5a to be dissipated. For this reason, heat dissipation efficiency can be improved.

  In the above-described forming method of the present invention, the radiating fins 5a are erected vertically with respect to the plane of the metal plate 2. However, in order to further improve the radiating performance, the radiating fins 5a are within 10 degrees. In some cases, the angle is slightly inclined. In this case, the radiating fin 5a that is slightly inclined can be formed by moving the blade portion 6a of the digging tool 6 at a predetermined angle with respect to the plane of the metal plate 2 in the correction step. That is, in the present invention, the term “perpendicular” includes the radiating fins 5a slightly inclined.

  In the method of forming the radiating fin 5a described above, when the thickness of the radiating fin 5a is as thin as 0.1 mm to 0.8 mm, the blade 6a of the digging process is moved vertically from the digging process to the correction process. It can be performed. However, when the digging process is performed with the digging tool 6, as shown in FIG. 7A, the tip of the blade portion 6a is in a state of being bitten into the base portion of the radiating fin 5a. For this reason, when the plate | board thickness of the radiation fin 5a exceeds 0.8 mm, when it transfers to the correction process from the state which the blade part 6a digged in, it will become a big load with respect to the blade part 6a, and the blade part 6a may be damaged depending on the case. there's a possibility that. In this way, when the radiating fin 5a is relatively thick, as shown in FIG. 7B, the digging tool 6 is retracted by a slight dimension from the position where the digging process is completed, and the radiating fin 5a is inclined. A gap is provided between the side surfaces of Thereafter, as shown in FIG. 7 (C), the cutting step 6a of the digging tool 6 is moved in the vertical direction to move the radiating fins 5a vertically, and as shown in FIG. By performing the above, it is possible to reduce the load on the blade portion 6a at the start of the correction process and prevent damage.

  On the other hand, on the upstream side of the radiating fin 5b opposite to the small fin 5a, the last radiating fin 5a is formed on the upstream side of the metal plate 2 from the bottom surface 2e as shown in FIGS. An inclined workpiece surface 2d that remains is left. The inclined surface that is the surface to be processed 2d can act as a heat radiating surface. In addition, a flange portion 7 having a thickness of the metal plate 2 is formed behind the processed surface 2d.

  Further, on both sides of the plurality of radiation fins 5 b formed on the metal plate 2, the flange portions 7 having the thickness of the metal plate 2 are formed. The flange portion 7 can be formed by setting the width of the digging tool 6 to be narrower than the width of the metal plate 2. As a result, as shown in FIG. 1, the flange portion 7 formed in the radiator 1 is formed so as to surround the heat radiating portion 5.

  The heat dissipating part 5 is formed at a position corresponding to an electronic component such as an integrated circuit 8 disposed in a wiring pattern formed of the metal foil 3 on the one surface 2a of the metal plate 2. By installing the heat dissipating part 5 in such a positional relationship, heat generated from the integrated circuit 8 is transmitted to the heat dissipating part 5 through the metal plate 2 and is dissipated from the surface of the heat dissipating fins 5b into the air. The base ends of the small fins 5a and the heat radiating fins 5b are integrally connected from the bottom surface 2e formed on one surface of the metal plate 2, and the thickness between the bottom surface 2e and the one surface 2a of the metal plate 2 is as follows. Since it is formed thinly, heat generated from the integrated circuit 8 is quickly transferred to the heat radiating portion 5, and it has been clarified through experiments that the heat radiation efficiency is improved. In addition to the integrated circuit 8, the electronic component includes a power transistor, a resistor, a power module, and the like.

  Although the present invention has been specifically described above based on the embodiments, it is needless to say that the present invention is not limited to the above embodiments and can be variously modified without departing from the gist thereof. For example, the metal-based printed board may be formed in an appropriate shape in the same manner as a general printed board other than a square. In the above-described embodiment, the heat radiating portion is formed at one place. However, it may be formed at a plurality of places according to the arrangement position of the integrated circuit or the like that requires heat radiating. In this case, the direction of the radiating fins may be varied at an appropriate angle for each radiating portion. Furthermore, since the metal base printed board uses a metal plate as a base substrate, other mechanical parts or the like may be attached, or a support part or the like may be provided so as to attach the mechanical parts.

DESCRIPTION OF SYMBOLS 1 Metal base printed circuit board 2 Metal plate 2a One side 2b The other side 2c One end side 2d Processed surface 2e Bottom surface 3 Metal foil 4 Insulation adhesive layer 5 Heat radiation part 5a Small fin 5b Radiation fin 6 Digging tool 6a Blade part

Claims (2)

A metal foil is bonded to one side of a metal plate having a predetermined thickness with thermal conductivity via an adhesive layer, and the other side of the metal plate is formed with a plurality of vertically standing at predetermined intervals. It is a metal base printed board having a heat radiation part integrally formed with a plate-shaped heat radiation fin,
The plurality of plate-like heat radiating fins are vertically formed from the metal plate, and are formed with substantially equal thicknesses from the base end portion integrally connected to the metal plate to the tip end,
A metal base printed board with a heat radiating portion, wherein the thickness of the bottom surface formed between the heat radiating fins adjacent to the heat radiating portion is smaller than the thickness of the metal plate. A metal foil is bonded to one side of a metal plate having a predetermined thickness via an adhesive layer, and a plurality of plate-like heat radiation fins that are vertically erected at predetermined intervals are formed on the other side of the metal plate. It is a metal base printed circuit board having an integrally formed heat dissipation part,
The radiating fin has a digging tool having a blade portion formed on the tip side moved by a moving device directed toward one surface of the metal plate in a state having a predetermined angle with respect to the other surface of the metal plate. An excavation step of standing and forming an inclined plate-like fin by moving it and digging it down, and raising the excavating tool in a vertical direction while bringing the blade portion into contact with the inclined fin and against the plane of the metal material A plurality of plate-like heat dissipating fins in a standing manner by sequentially repeating a straightening process for standing upright and a receding process in which the excavating tool is retracted to a position where the next fin is spaced apart by a predetermined distance. A heat dissipating part and a heat dissipating fin forming method for a metal base printed circuit board.

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